In the introductory chapter, the author writes "This book explores some important tools for gathering firsthand information on spouses, CEOs, politicians and the girl next door." There aren't too many techniques for eavesdropping on CEOs or politicians in this book, so we assume the average reader would be concentrating on the other targets. The author describes himself as a semi-retired private investigator. Like most authors within this genre he tells a few war stories, but his clients mostly seem to be suspicious husbands or wives and a couple of insurance or workers compensation cases. So this is a book on how to eavesdrop on soft targets.
The book is not technically demanding and relies heavily on converting consumer products readily available at Radio Shack in North America but mostly unknown elsewhere. There is almost nothing here for foreign readers. He spends about six pages explaining how to convert a "Mr Microphone" toy into a room bug, and how to modify its frequency to outside the FM broadcast band, as wells as using it as a phone tap. He has a circuit diagram of a home brew bug (nothing original here). He spends thirteen pages on the design of a DTMF tone decoder, a product there is little difficulty in buying these days. He also takes ten pages to describe how to defraud North American telephone companies with a "red box" a well known circuit, but useless in the rest of the world and rapidly becoming useless in the USA.
As an investigator he relies heavily on monitoring older style analogue cordless phones and baby monitors with a scanner. There are eighteen pages describing how to eavesdrop on the North American analogue mobile phone network (the rest of the world has moved on to secure digital phones). There are also several pages on how to hack into answering machines, a topic better covered in numerous Internet sites.
The bibliography is of little practical use and seems chosen at random. The author lists two web sites (and he has a third recently set up) where you will find corrections and a bulletin board but whose main purpose seems to be to market his other books and to sell his DTMF decoder.
There is little here for the electronics professional and nothing to justify the price for a reader outside the US and Canada
A word of caution here. Most governments have made illegal the construction, possession, distribution (by sale or otherwise), use or use of material obtained from eavesdropping devices except in special circumstances so you are advised to check your local laws if you want to do more than read this book.
On the other hand, successful prosecutions are rare and similar devices are openly advertised for sale. Detection of these devices is difficult. Any competent hobbyist could produce this equipment from readily available components or by disassembly of consumer items.
But before you go into business consider This advice. Whether your clients are cops, spies or gangsters, they are eavesdroppers and conspirators - they are inherently untrustworthy. They don't regard you as an electronic genius - you're just the hired help, some geek who is useful but expendable. Look after number one! The smartest player is often the one who does not join the game.
